title: Digital Evaluation of Functional Occlusion Parameters and their Association with Temporomandibular Disorders.
abstract: BACKGROUND
  Dental researchers are contradictory in their opinion on the role of occlusion in TMD. Occlusal evaluation of both conventional and digital methods in TMD patients will provide the accurate information about the factors accountable for occlusal instability. Identifying the factors responsible will facilitate precise diagnosis and treatment for TMD.
  
  
  OBJECTIVE
  The AIM of the study was to determine the dynamic occlusal parameters strongly associated with the etiology of Temporomandibular disorders.
  
  
  METHODS
  Study group consisted of 100 patients; it included 50 patients with normal TMJ(Group I) and remaining 50 patients had a minimum of one positive sign or symptom of Temporomandibular disorder (GroupII). The patient's dynamic occlusal contacts were evaluated by both conventional and digital methods. The Articulating paper was utilized for conventional occlusion analysis. During conventional analysis centric, lateral and protrusive interferences were evaluated along with loss of vertical dimension. Digital occlusal analysis was performed with T-Scan III. Clusion time, disclusion times were recorded for both groups. Chi-square and Student't' statistical analyses were performed to ascertain the association and statistically significant difference between the groups using SPSS19.
  
  
  RESULTS
  Group II patients predominantly (66%)had Group-function occlusion compared to Group I subject. Centric slide more than 2 mm found to have strong influence (p value 0.008) on the etiology of TMD. Among the occlusal interferences evaluated balanced side interferences had a strong correlation with TMD with p-value of 0.003. Working side interferences, protrusive interferences had a p-value of 0.157, 0.826 respectively, indicating weak association. T-Scan analysis showed Group I had 0.689, 0.9136, 0.7952, 0.9794 seconds of clusion, left, right, protrusive disclusion time respectively compared to corresponding 1.862, 1.7995, 1.6978, 1.9296 seconds for Group II. Statistically significant difference (p≤0.05) was found between the mean values of both groups.
  
  
  CONCLUSIONS
  Among the dynamic occlusal parameters evaluated centric slide and balancing side interferences were found to be highly influential in TMD etiology. TMD patients had prolonged clusion and disclusion times compared to healthy TMJ patients.
authors.affiliation: Assistant Professor/Assistant Clinical Director, Department of Prosthodontics, College of Dentistry, King Khalid university , Abha, Kingdom of Saudi Arabia .
authors.forename: Satheesh B
authors.initials: SB
authors.lastname: Haralur
keywords: Dynamic occlusal interferences; Occlsual evaluation; T-Scan III; TMD